Methods of manufacturing an antenna for an implantable electronic device and related implantable electronic devices

ABSTRACT

Methods for manufacturing implantable electronic devices include forming an antenna of the implantable electronic device by delivering an antenna trace within a dielectric antenna body. The antenna trace includes a first trace portion disposed in a first transverse layer and defining a first trace path and a second trace portion disposed in a second transverse layer longitudinally offset from the first transverse layer and defining a second trace path. If projected to be coplanar, the first trace path defines a trace boundary and the second trace path is within the trace boundary.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application U.S. application Ser. No.17/512,420, filed 27 Oct. 2021, which is a continuation application ofU.S. application Ser. No. 16/773,195, filed 27 Jan. 2020 (now U.S. Pat.No. 11,189,915, issued 30-Nov.-2021), which is a continuation of U.S.application Ser. No. 15/633,614, filed 26-Jun.-2017 (now U.S. Pat. No.10,587,038, issued 10 Mar. 2020), which claims the benefit of U.S.Provisional Patent Application No. 62/419,868, filed 9 Nov. 2016 (nowexpired). The contents of the above-mentioned patent applications arehereby incorporated by reference in their entirety.

FIELD OF THE INVENTION

Aspects of the present invention relate to medical apparatus andmethods. More specifically, the present invention relates to systems andmethods for implementing an antenna on an implantable medical device.

BACKGROUND OF THE INVENTION

Implantable pulse generators (IPGs) such as pacemakers and implantablecardioverter defibrillators (ICDs), which are used in the treatment ofcardiac conditions, and neuromodulators or neurostimulators, which areused in chronic pain management or the actuation and control of otherbody systems, commonly include a hermetically sealed housing,feedthrough pins, and a connector assembly that is enclosed in a header.Electrical stimulation originating in the housing is led to theconnector assembly through feedthrough pins. The connector assemblyserves to transmit electrical signals out of the IPG and to a leadelectrically connected to the connector assembly, the lead transmittingelectrical signals between the IPG and patient tissue. Certain IPGs arefurther adapted to sense tissue activity, such as intrinsic heartactivity, of a patient.

The connector assembly of an IPG generally includes a wide range ofcomponents including, without limitation, lead connectors, feedthroughpins, and conductors for coupling the lead connectors to the feedthroughpins. The header may further house an antenna for enabling wirelesscommunication between the electrical circuitry of the IPG and externalcomputing devices. Such computing devices may be used, among otherthings, to configure settings of the IPG, to perform tests and otherdiagnostics of IPG components, and to collect performance data that ismeasured and stored by the IPG during operation.

With the quantity and size of components maintained within the header,space is at a premium and critical components, such as lead connectors,are often given priority over antennas with regards to header space. Asa result of such space limitations, antennas for use in IPGs are oftenlimited in their length and communication capabilities.

Accordingly, there is a need in the art for systems and methods directedto antennas suitable for use within the limited space of an IPG header.

BRIEF SUMMARY OF THE INVENTION

The implantable electrical devices and methods disclosed herein includeantenna assemblies adapted for use in the relatively limited spaceavailable within an implantable electrical device header. In oneembodiment, a first implantable electronic device including ahermetically sealed housing containing an electrical circuit furtherincludes an antenna assembly coupled to the electrical circuit. Theantenna assembly defines a longitudinal axis and includes an antenna.The antenna includes a dielectric antenna body extending along thelongitudinal axis within which an antenna trace is disposed. The antennatrace includes a first trace portion disposed in a first transverselayer and defining a first trace path, a second trace portion disposedin a second transverse layer longitudinally offset from the firsttransverse layer and defining a second trace path, and a junctionextending longitudinally, at least in part, and coupling the first traceportion to the second trace portion. When projected to be coplanar, thefirst trace path defines a trace boundary within which the second tracepath is contained.

In one implementation of the present disclosure, the antenna furtherincludes a capacitive feature that extends from at least one of thefirst or second trace portions to at least partially overlap the secondor first trace portion, respectively, with a portion of the antenna bodydisposed there between. In a corresponding implementation, thecapacitive feature includes a tab extending from the first or secondtrace portion.

In another implementation, each of the dielectric antenna body and theantenna trace are composed of a biocompatible material. For example, thedielectric antenna body may be composed of one of alumina ceramic,liquid crystal polymer, and perovskite ceramic and the antenna trace maybe composed of gold or platinum.

In yet another implementation, the implantable electronic deviceincludes a feedthrough pin electrically coupled to the electricalcircuit and extending through the housing and the antenna assemblyfurther includes a mounting arm electrically coupled to each of theantenna trace and the feedthrough pin. In certain relatedimplementations, the antenna includes a transverse surface and themounting arm includes a coupling feature extending across the transversesurface. In such implementations, a capacitive feature may be disposedbetween the coupling feature and the transverse surface such that thecapacitive feature overlaps one of the first trace portion or the secondtrace portion with a portion of the antenna body disposed there between.The antenna assembly may further include a shroud coupled to each of theantenna body and a terminal end of the mounting arm, the shroud defininga receptacle into which the mounting arm is inserted.

In still another implementation, the antenna trace may further include athird trace portion disposed in a third transverse layer of the antennabody and defining a third trace path. In such implementations, thetransverse layers are arranged such that the second transverse layer isdisposed between the first and third layers. Also, if projected to becoplanar, the second trace path defines a second trace boundary withinwhich the third trace path is contained.

In another embodiment, an implantable electronic device includes a firstimplantable electronic device including a hermetically sealed housingcontaining an electrical circuit further includes an antenna assemblycoupled to the electrical circuit. The antenna assembly includes adielectric antenna body defining a longitudinal axis and an antennatrace disposed within the antenna body and arranged in a plurality oftransverse trace layers. The trace layers are shaped and arranged toreduce the capacitive coupling between the trace layers relative to anarrangement in which the trace layers are all overlapping. The antennaassembly further includes at least one capacitive feature. Eachcapacitive feature overlaps a respective portion of the antenna tracesuch that a corresponding portion of the antenna body is disposed therebetween.

In one implementation of the present disclosure, the capacitive featureextends from a first layer of the plurality of trace layers and overlapsa second layer of the plurality of trace layers.

In another implementation, the implantable electronic device furtherincludes a feedthrough pin coupled to the electrical circuit andextending through the housing and the antenna assembly further includesa mounting arm that electrically couples the feedthrough pin to theantenna trace. In certain embodiments, the capacitive feature includes aplate coupled to the mounting arm.

In yet another embodiment, each trace layer of the plurality of tracelayers defines a respective trace path and a respective trace boundary.Further, the trace layers are ordered such that, if projected to becoplanar, each respective trace path is within the respective traceboundary of a preceding trace layer.

In yet another embodiment, a method of manufacturing an implantableelectronic device is provided. The method includes forming an antenna bydelivering an antenna trace within a dielectric antenna body. Theantenna trace includes a first trace portion disposed in a firsttransverse layer and defining a first trace path and a second traceportion disposed in a second transverse layer longitudinally offset fromthe first transverse layer and defining a second trace path. Ifprojected to be coplanar, the first trace path defines a trace boundaryand the second trace path is within the trace boundary.

In one implementation, the method further includes tuning the antenna byforming one or more capacitive features that at least partially overlapat least one of the first trace portion or the second trace portion suchthat a portion of the antenna body is disposed there between. In acorresponding implementation, the capacitive features extend from thefirst trace portion to partially overlap the second trace portion and/orextend from the second trace portion to partially overlap the firsttrace portion.

In another implementation, the implantable electronic device includes afeedthrough pin. The method further includes coupling the antenna to aconductive mounting arm and coupling the mounting arm to the feedthroughpin such that the mounting arm electrically couples the antenna to thefeedthrough pin. In such implementations, the method may further includetuning the antenna by coupling a capacitive feature to the mounting armsuch that the capacitive feature overlaps at least one of the firsttrace portion or the second trace portion with a portion of the antennabody disposed there between.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of a proximal end portion (i.e., leadconnector end) of a conventional transvenous bipolar pacing lead.

FIG. 2 is an isometric view of a cardiac pacemaker/defibrillator unit(i.e., implantable pulse generator (IPG)) incorporating connectorjunctions or terminals for communication with one or more electrodes.

FIG. 3A is an isometric view of a representative header.

FIG. 3B is an isometric view of a representative connector assembly andfirst antenna assembly used within the header of FIG. 3A to form aheader connector assembly.

FIG. 4A is a side view of an implantable pulse generator including asecond representative connector assembly and a second antenna assembly.

FIGS. 4B-4D are, respectively, an enlarged side view and two generallyopposite isometric views of the second representative connector andantenna assemblies of FIG. 4A.

FIGS. 5A-5B are, respectively, a side view and an end view of a thirdconnector assembly and a third antenna assembly.

FIGS. 6A-6B are, respectively, a side view and an end view of a fourthconnector assembly and a fourth antenna assembly.

FIG. 7 is an isometric view of a generic antenna in accordance with thisdisclosure.

FIG. 8A is an isometric view of a fifth antenna assembly.

FIGS. 8B-8C are, respectively, a plan view and a side view of theantenna assembly of FIG. 8A.

FIG. 9A is an isometric view of a sixth antenna assembly.

FIG. 9B is a plan view of the antenna assembly of FIG. 9A.

FIG. 10 is a plan view of a seventh antenna assembly.

FIG. 11A is a side view of an eighth antenna assembly.

FIGS. 11B-11C are, respectively, a plan view and an isometric view ofthe antenna assembly of FIG. 11A.

FIGS. 12A-12B are, respectively, a side view and an enlarged side viewof a ninth antenna assembly.

FIG. 12C is a plan view of an antenna of the antenna assembly of FIGS.12A-12B.

FIG. 13 is an isometric view of a tenth antenna assembly.

DETAILED DESCRIPTION

Implementations of the present disclosure involve an implantable pulsegenerator (IPG) for administering electrotherapy or otherneurostimulation via an implantable lead having a lead connector end ona proximal end of the implantable lead. The IPG includes a housing orcan and a connector assembly enclosed in a header, both of which arecoupled to the housing or can. The header and connector assembly combineto form at least one lead connector receiving bore or receptacle thatincludes electrical contacts that make electrical contact withcorresponding electrical terminals on the lead connector end on theproximal end of the implantable lead when the lead connector end isplugged into or otherwise received in the lead connector receiving boreor receptacle. Via the electrical connection between the correspondingelectrical terminals of the lead connector end and the electricalcontacts of the lead connector receiving bore, electrical signals can beadministered from the IPG and through the lead to patient tissue.Similarly, but in reverse, electrical signals originating in patienttissue can travel via the lead to the IPG to be sensed at the IPG.

In conventional IPGs, space within the header is limited. The wide rangeof parts associated with the connector assembly, in particular, requiresa significant portion of the space within the header. Notably, manyparts associated with the connector assembly are unable to be eliminatedor miniaturized. For example, standards, and regulations often dictatethe minimum sizes of leads and lead connectors. Many such standards andregulations are rooted in practical considerations regarding a doctor orsurgeon's ability to manipulate the components while wearing gloves andwhile handling the components in a wet environment. Accordingly, thedimensions of an antenna within the header are often limited by thespace considerations other components.

To address the size limitations imposed by IPG headers, antennas andantenna assemblies in accordance with this disclosure include antennabodies composed of dielectric materials within which an antenna trace isdisposed. The antenna is generally coupled to a conductive mounting armthat mounts to a feedthrough pin extending out of the IPG housing.

Antennas in accordance with this disclosure include traces distributedwithin the antenna body in multiple transverse trace layers. Each layerof the antenna trace is shaped to be non-overlapping with the othertrace layers. More specifically, the trace layers are arranged such thatsuccessive trace layers define progressively decreasing boundaries thatencompass the boundaries of subsequent trace layers. As a result, a longantenna length can be accommodated while reducing the capacitivecoupling between adjacent trace layers.

Tuning of the antenna may be achieved by selective placement ofcapacitive features within the antenna. In certain implementations, thecapacitive features are tabs or similar structures that extend from onelayer of the antenna trace to overlap a portion of a second layer of theantenna trace such that a portion of the antenna body is disposedbetween the tab and the portion of the second layer. In otherimplementations, the capacitive feature is a plate or tab coupled to themounting arm such that the plate or tab overlaps a portion of a tracelayer. In either case, a capacitive structure is formed in which thecapacitive feature forms a first plate, the overlapped antenna traceportion forms a second plate, and the portion of the antenna body actsas the dielectric between the two plates. By adjusting the amount ofoverlap between the capacitive feature and the trace layer, the materialof the antenna body, and the distance between the capacitive feature andthe overlapped trace layer, the capacitance of the capacitive structureand, as a result, the performance characteristics of the antenna may betuned to suit a particular application.

Before beginning a detailed discussion of the antenna and antennaassembly, a general discussion is first given regarding features of acommon lead connector end at the proximal end of an implantable medicallead followed by a general discussion of the features of an IPG. Whilethe teachings disclosed herein are given in the context of an IPG, theteachings are equally applicable to implantable medical monitors (e.g.,implantable cardiac monitors) or any other implantable electronic deviceemploying an antenna assembly.

FIG. 1 shows a proximal end portion 10 of a conventional transvenous,bipolar pacing lead, but is generally representative of any type ofimplantable lead whether in the cardiac, pain management, deep brainstimulation, or other medical treatment space. The diameter of such alead may be made a sufficiently small diameter to facilitate the lead'simplantation into small veins such as those found in the coronary sinusregion of the heart and to allow implantation of a plurality of leadsinto a single vessel for multi-site or multi-chamber pacing. It shouldbe understood, however, that other lead designs may be used, forexample, mulitpolar leads having proximal end portions that arebifurcated, trifurcated or have other branched configurations. While thelead whose proximal end is shown in FIG. 1 is of the bipolar variety,there are unipolar leads that carry but a single electrode, andmultipolar leads that have more than two electrodes.

As is well known in the art, bipolar coaxial leads typically consists ofa tubular housing of a biocompatible, biostable insulating materialcontaining an inner multifilar conductor coil that is surrounded by aninner insulating tube. The inner conductor coil is connected to a tipelectrode on the distal end of the lead. The inner insulating tube issurrounded by a separate, outer multifilar conductor coil that is alsoenclosed within the tubular housing. The outer conductor coil isconnected to an anodal ring electrode along the distal end portion ofthe lead. The inner insulation is intended to electrically isolate thetwo conductor coils preventing any internal electrical short circuit,while the housing protects the entire lead from the intrusion of bodyfluids. These insulating materials are typically either silicone rubberor polyurethane. More recently, there have been introduced bipolar leadsin which multifilar cable conductors contained within multilumenhousings are substituted for the conductor coils in order to reduce evenfurther the overall diameter of the lead.

The proximal lead end portion 10 shown in FIG. 1 includes a leadconnector end 11 that conforms to the IS-1 standard, comprising a pairof coaxial spaced-apart electrical terminals including a tip terminal 12and a ring terminal 14. The tip terminal 12 is electrically connected bymeans of the inner conductor coil to the tip electrode at the distal endof the lead, while the ring terminal 14 is electrically connected to theanodal ring electrode by means of the outer conductor coil. The tip andring terminals of the lead connector end may each be engaged by aconductive garter spring contact or other resilient electrical contactelement in a corresponding lead connector receiving bore of the header,the resilient electrical contact element being carried by a connectorassembly enclosed in the header as described below. The lead connectorend 11 on the proximal lead end portion 10 further comprisesspaced-apart pairs of seal rings 16 for abutting against in afluid-sealing manner the inner circumferential surface of the leadconnector receiving bore of the header, thereby preventing body fluidsfrom reaching the electrical terminals and contacts when the leadconnector end 11 is plugged into the corresponding lead connectorreceiving bore. With the lead connector end 11 of the lead inserted inthe lead connector receiving bore of the header and connector assembly,the tip and ring terminals 12 and 14 are electrically coupled via thecontacts of the connector assembly and a feedthrough to the electroniccircuits within the hermetically sealed housing of the IPG (e.g.,cardiac pacemaker, ICD, or other implantable tissue stimulation and/orsensing device such as those used in pain management, etc.).

FIG. 2 shows an IPG 20 that may be, among other devices, a multi-site ormulti-chamber cardiac pacemaker/defibrillator unit. The IPG 20 isgenerally representative of any type of IPG incorporating a headerconnector assembly 22 coupled to a housing 24. The header connectorassembly 22 includes a header 40 enclosing a connector assembly 42, bothof which are depicted respectively in FIGS. 3A and 3B discussed below.The IPG 20 is of a conventional design, including a hermetically sealedhousing 24, which is also known as a can or casing. The housing 24encloses the electronic components of the IPG 20 with the headerconnector assembly 22 mounted along a top edge 26 of the housing 24.

FIG. 2 illustrates that, in some embodiments, the header connectorassembly 22 may include four or more lead connector receiving bores orreceptacles 30, 31, 32 and 33 for receiving the lead connector ends offour implantable leads. FIG. 2 also shows the proximal end portion 10 ofa lead, wherein the lead connector end on the proximal end portion 10 ofthe lead is received in a corresponding receptacle 32. In otherembodiments, the header connector assembly 22 includes two receptaclescomprising a single pair of receptacles (i.e., receptacles 30 and 33)for receiving the proximal ends of leads such as, for example,conventional bipolar leads and/or conventional cardioverting and/ordefibrillating leads.

FIG. 3A is an isometric view of a representative header 40 and FIG. 3Bis an isometric view of a representative connector assembly 42 andantenna assembly 50. Unlike the header connector assembly 22 of FIG. 2 ,the header 40 of FIG. 3A only has a single pair of receptacles 30 and33. However, in other embodiments, the header 40 of FIG. 3A may have twoor more pairs of receptacles similar to the embodiment of FIG. 2 .

As illustrated in FIG. 3B, the connector assembly 42 includes tip blocks44 and ring blocks 46. The ring blocks 46 include spring contacts 48.Each electrical block 44 and 46 of the connector assembly 42 serves asan electrical contact of the connector assembly 42. Thus, as can beunderstood from FIGS. 1, 2 and 3B, each tip block 44 is configured toreceive and make electrical contact with the tip terminal 12 of a leadconnector end 11 received in the corresponding receptacle 30, 33 of theheader 40. Similarly, each ring block 46 is configured to receive andmake electrical contact with the ring terminal 14 of a lead connectorend 11 received in the corresponding receptacle 30, 33 of the header 40.While the connector assembly 42 of FIG. 3B is of an IS-1 configuration,other configurations (e.g., IS-4, etc.) are used in other embodiments.While the connector assembly 42 of FIG. 3B only depicts two pairs ofblocks 44, 46, in other embodiments where the header includes more thana single pair of receptacles 30, 33 (e.g., two pairs of receptacles 30,31, 32, 33 as indicated in FIG. 2 ), the connector assembly 42 will havea four pairs of blocks 44, 46.

As shown in FIG. 3B, the connector assembly 42 also includes an A-tiptab 54, an A-ring tab 56, an RV-ring tab 58, and an RV-tip tab 60 andother conductors that extend between the various tabs and theirrespective electrical contacts of the connector assembly 42 or othercomponents thereof. The various tabs are welded or otherwise coupled tocorresponding terminals extending from circuitry of the IPG 20 containedin the housing 24 of the IPG 20 depicted in FIG. 2 when the headerconnector assembly 22 is joined with the housing 24 to form the IPG 20.In the implementation illustrated in FIG. 3B, for example, the IPG 20includes a pin bank 62 including multiple feedthrough pins, such asfeedthrough pin 64. Each feedthrough pin is coupled to an electricalcircuit within the IPG 20 and extends through the housing 24 of the IPG20 while preserving the hermetic seal of the housing 24. The feedthroughpin is then welded or otherwise coupled to one of the tabs of theconnector assembly 42. For example, the feedthrough pin 64 is coupled tothe RV-tip tab 60. The connector assembly 42 is manufactured ofmaterials and via methods known in the industry. The connector assembly42 may be molded into the header 40 to form the header connectorassembly 22 of FIG. 2 , which can be considered a first module that isthen anchored to a second module in the form of the housing 24. Theheader connector assembly 22 (i.e., first module) may be anchored to thehousing 24 (i.e., the second module) via systems and methods known inthe art.

The IPG 20 further includes an antenna assembly 50, which includes anantenna 52 coupled to a mounting arm 66. The mounting arm 66 is mountedto a pin (hidden within the mounting arm 66) of the pin bank 62. Theantenna assembly 50 facilitates radio frequency (RF) communicationbetween the IPG 20 and one or more external computing systems.Communication may occur using one or more proprietary or standardprotocols including, without limitation, Wi-Fi, Bluetooth, Bluetooth lowenergy, Zigbee, and IEEE 802.15.4. Data received from an externalcomputing device by the IPG 20 through the antenna assembly 50 mayinclude, without limitation, one or more of commands, configurationdata, and software/firmware updates. Data sent by the IPG 20 to anexternal computing device may include, without limitation, one or moreof device settings of the IPG 20, patient data collected duringoperation of the IPG 20, and diagnostic data regarding functionality ofthe IPG 20.

FIGS. 4A-4D are schematic illustrations of a second embodiment of an IPG120 including an antenna assembly 150 in accordance with thisdisclosure. The IPG 120 includes a hermetically sealed housing 124coupled to a connector assembly 142. As shown in FIG. 3A, a cover (e.g.,header 40) is generally disposed over the connector assembly 142,however, for purposes of clarity, such a cover is not included in FIGS.4A-4D. The connector assembly 142 includes three connector blocks 144,146, 148 adapted to receive terminals of leads (not shown). Theconnector block 144 includes two terminals 180, 182 adapted to makeelectrical contact with terminals of a lead inserted into the connectorblock 144. Similarly, the connector blocks 146, 148 each include fourterminals (for example, connector block 146 includes terminals 184-190)similarly adapted to make electrical contact with terminals of a leadinserted into the connector blocks 146, 148. To facilitate communicationbetween the connector blocks 144-148 and internal circuitry of the IPG20, each terminal of the connector blocks 144-148 is connected by aconductor to a feedthrough pin of a feedthrough pin bank. For example,in the embodiment of FIGS. 4A-4D the connector assembly 142 includes twofeedthrough pin banks 156, 158 and the terminal 190 of the connectorblock 146 is coupled to the feedthrough pin bank 158 by a conductor 192.

The connector assembly 142 further includes an antenna assembly 150coupled to a pin of the feedthrough pin bank 156. The antenna assembly150 includes an antenna 152 coupled to a mounting arm 154. As mostclearly shown in FIGS. 4B-4D, the mounting arm 154 is coupled to afeedthrough pin 160 of the feedthrough pin bank 156. As shown in FIGS.4C and 4D, the mounting arm 154 may then extend vertically and away fromthe feedthrough pin bank 156 such that the antenna 152 is positioned toavoid interference with the feedthrough pin bank 156, the connectorblocks 144-148, or any conductors extending between the connector blocks144-148 and the feedthrough pin bank 156.

Arrangements of the various components of the connector assembly 142 arenot limited to that illustrated in FIGS. 4A-D. For example, placement ofthe antenna assembly 150 may vary based on the size and shape of theantenna assembly 150; the size, quantity, and arrangement of connectorblocks within the connector assembly 142; the size, quantity andarrangement of feedthrough pin blocks within the connector assembly 142;and the quantity and routing of conductors extending between connectorblocks and feedthrough pin blocks of the connector assembly 142.

Although the antenna 152 of the antenna assembly 150 is generally shownas having an elongated or rectangular shape, other antenna shapes arepossible. For example, FIGS. 5A-5B illustrate a connector assembly 242including an antenna assembly 250. The antenna assembly 250 furtherincludes a square antenna 252 coupled to a mounting arm 254. Similarly,FIGS. 6A-6B illustrate a connector assembly 342 including an antennaassembly 350 having a circular antenna 352 coupled to a mounting arm354. Moreover, and as discussed in more detail below, while FIGS. 4A-7Binclude antennas arranged in a substantially vertical orientation, otherorientations may be possible. For example, FIGS. 7-13 illustrateantennas having substantially horizontal orientations.

FIG. 7 is an illustration of an antenna 400 in accordance with thisdisclosure. The antenna 400 includes an antenna body 402 within which anantenna trace 404 is disposed. Although illustrated in FIG. 7 as havinga rectangular shape, the antenna body 402 is not limited to a particularsize or shape. Nevertheless, the antenna body 402 generally defines alongitudinal axis 450 and extends in a longitudinal direction 452.

The antenna trace 404 runs continuously through the antenna body 402 andis distributed across multiple layers within the antenna body 402. Forexample, the antenna trace 404 of FIG. 7 includes a first trace portion406 in a first layer and a second trace portion 408 in a second layer,each of the first and second layers being transverse relative to thelongitudinal axis 450 and offset from each other. The first traceportion 406 and second trace portion 408 are joined by an interlayerjunction 410 extending substantially in the longitudinal direction 452.The antenna 400 may further include a terminal junction 416 disposed atan opposite end of the first trace portion 406 from the interlayerjunction 410. The terminal junction 416 is further coupled to a plate418 which may be coupled to a mounting arm or similar conductivestructure to facilitate conduction of electrical signals to and from theantenna 400.

FIGS. 8A-8C illustrate an antenna assembly 500 including an antenna 502and a mounting arm 560. The antenna 502 has a generally rectangularshape and includes an antenna body 504 within which an antenna trace 505is disposed. The antenna 502 is coupled to the mounting arm 560 suchthat the antenna 502 is maintained in a substantially horizontalorientation. The antenna trace 505 includes a first trace portion 506coupled to a second trace portion 508 by an interlayer junction 510. Thefirst trace portion 506 and the second trace portion 508 are arranged inoffset transverse layers relative to a longitudinal direction 552 alongwhich the antenna body 504 extends.

The antenna body 504 is generally composed of one or more dielectricmaterials and the antenna trace 505 of one or more conductive materials.Antennas in accordance with this disclosure are generally implantedwithin a patient and, as a result, such materials may further bebiocompatible. For example, the antenna body 504 may be composed of aceramic or plastic including, without limitation, one or more of analumina ceramic, a liquid crystal polymer, and a perovskite ceramic andthe antenna trace 505 may be composed of one or more conductive metalsincluding, without limitation, gold and platinum.

Referring to FIG. 8B, the first trace portion 506 and the second traceportion 508 define a first trace path 512 and a second trace path 514,respectively. The first trace path 512 and the second trace path 514 arearranged such that the first trace portion 506 and the second traceportion 508 are non-overlapping, thereby reducing capacitive couplingbetween the trace portions 506, 508. More generally, the first tracepath 512 and the second trace path 514 are defined such that whenarranged to be coplanar, the first trace path 512 defines a boundarywithin which the second trace path 512 is contained. Although the firsttrace path 512 and the second trace path 514 are shown in FIG. 8B asconcentric squares, antennas in accordance with this disclosure are notlimited to such arrangements and may include different and/or offsetshapes in each transverse layer provided the second trace path 514 iscontained within the boundary defined by the first trace path 512.

The first trace portion 506 may further be coupled to a terminaljunction 516 extending from a conductive pad 518. The conductive pad 518is in turn electrically coupled to the mounting arm 560. The mountingarm 560 is generally composed of a conductive material such thatelectrical signals can be transmitted between the antenna 502 and afeedthrough pin to which the mounting arm 560 is coupled.

FIGS. 9A-9B illustrate an alternative antenna assembly 600 including anantenna 602 and a mounting arm 660. Similar to the antenna 500 of FIGS.8A-8C, the antenna 602 has a generally rectangular shape and includes anantenna body 604 within which an antenna trace 605 is disposed. Theantenna 602 is coupled to the mounting arm 660 such that the antenna 602is maintained in a substantially horizontal orientation. The antennatrace 605 includes a first trace portion 606 coupled to a second traceportion 608 by an interlayer junction 610. The first trace portion 606and the second trace portion 608 are arranged in offset transverselayers relative to a longitudinal direction 652 along which the antennabody 604 extends.

Referring to FIG. 9B, the first trace portion 606 and the second traceportion 608 define a first trace path 612 and a second trace path 614,respectively. The first trace path 612 and the second trace path 614 arearranged such that they are generally non-overlapping. However, incontrast to the implementation illustrated in FIGS. 8A-8C, the secondtrace portion 608 further includes a plurality of capacitive featuresextending from the second trace portion 608 to selectively overlap thefirst trace portion 606. More specifically, tabs 620 extend from thesecond trace portion 608 to overlap the first trace portion 606. As aresult, capacitive structures are formed in which the tabs 620 form afirst set of plates, corresponding sections of the first trace portion606 form a second set of plates opposite the first set of plates, andthe dielectric material of the antenna body 604 provides the dielectricmaterial disposed between the two sets of plates.

The capacitive structures of the antenna 602 cause the antenna 602 to bethe equivalent of multiple parallel capacitors with each capacitorcorresponding to a single pair of a tab 620 and corresponding section ofthe first trace portion 606. As a result, the performancecharacteristics of the antenna 602 can be modified or tuned by adjustingthe capacitance of the tab 620 and first trace portion 606 pairings. Forexample, capacitance may be tuned by one or more of modifying the offsetbetween the first trace portion 604 and the second trace portion 606(thereby modifying the distance between the tabs 620 and the first traceportion 606), changing the material of the antenna body 604 (therebymodifying the dielectric constant of the material disposed between thetabs 620 and the first trace portion 606), and changing the amount ofoverlapping area between the tabs 620 and the first trace portion 606.Notably, while the material of the antenna body 604 and the spacingbetween the first and second trace portions 604, 606, affect all tabs620, the overlapping area of each tab 620 may be individually adjusted,thereby facilitating fine tuning of the capacitance of the antenna 602.

While the capacitive features of FIGS. 9A-9B are substantially squaretabs 620 extending from the second trace portion 606, other shapes,sizes, and arrangements of the capacitive features are possible. Forexample, in certain implementations, capacitive features, such as tabs,may extend from the first trace portion 604 to overlap with the secondtrace portion 606. As another example, the capacitive feature mayinclude a branch or bend extending from one of the first trace portion604 and the second trace portion 606 to overlap the second trace portion606 and the first trace portion 604, respectively. Moreover, anysuitable quantity of capacitive features may be included to achieve therequired tuning of the antenna 602.

FIG. 10 is a plan view of another example antenna assembly 700 thatincludes an antenna 702. The antenna includes an antenna trace 705disposed within an antenna body 704. The antenna trace includes a firsttrace portion 706 disposed in a first transverse layer and a secondtrace portion 708 disposed in a second transverse layer that is offsetfrom the first transverse layer. The antenna 702 includes a capacitivefeature 720 extending from the second trace portion 708 to overlap withthe first trace portion 706. More specifically, and in contrast to thetabs 620 shown in FIGS. 9A-9B, the capacitive feature 720 is in the formof an offshoot extending from the terminal end of the second traceportion 708. The offshoot 720 overlaps with a portion of the first traceportion 706, thereby creating a capacitive structure in which theoffshoot forms a first plate, the opposite portion of the first traceportion 706 forms a second plate, and the material of the antenna body704 acts as the dielectric between the first and second plates. Bymodifying the offshoot 720, the capacitance of the capacitive structurecan be adjusted to tune the antenna 702. For example, the capacitancemay be modified by changing the extent to which the offshoot 720 extendsalong the first trace portion 706.

FIGS. 11A-11C illustrate yet another antenna assembly 800 in accordancewith the present disclosure. The antenna assembly 800 includes anantenna 802 coupled to a mounting arm 860. The antenna 802 includes anantenna body 804 within which an antenna trace 805 is disposed. Theantenna trace 805 includes a first trace portion 806 coupled to a secondtrace portion 808 by a first interlayer junction 810 and furtherincludes a third trace portion 812 coupled to the second trace portion808 by a second interlayer junction 814. The trace portions 806-810 arearranged in offset transverse layers relative to a longitudinaldirection 852 along which the antenna body 804 extends.

FIGS. 11A-11C are intended to illustrate that antennas in accordancewith this disclosure may include any suitable number of layered traceportions. For example and with reference to FIG. 11B, the trace portions806-810 define trace paths 816-820, respectively. Each of the tracepaths 816-820 are arranged such that the corresponding trace portions806-810 are non-overlapping. More specifically, the first trace path 816and the second trace path 818 are defined such that when arranged to becoplanar, the first trace path 818 defines a boundary within which thesecond trace path 818 is contained. Similarly, the second trace path 818and the third trace path 820 are defined such that when arranged to becoplanar, the second trace path 818 defines a boundary within which thethird trace path 820 is contained. Capacitive features (not shown), suchas tabs, offshoots, and the like, may extend from any of the traceportions 806-810 to overlap and selectively form capacitive structureswith others of the trace portions 806-810, thereby facilitating tuningof the antenna 802.

FIGS. 12A-12C depict another antenna assembly 900 in accordance with thepresent disclosure. The antenna assembly 900 includes an antenna 902coupled to a mounting arm 960. The antenna includes an antenna body 904within which an antenna trace 905 (shown in FIGS. 12B-12C) is disposed.The antenna trace 905 includes a first trace portion 906 and a secondtrace portion 908 disposed on an offset layer from the first traceportion 906 within the antenna body 904. The first trace portion 906 andthe second trace portion 908 are shown as being non-overlapping suchthat capacitive coupling between the first trace portion 906 and thesecond trace portion 908 is minimized. In certain implementations, thefirst trace portion 906 and/or the second trace portion 908 may includetabs or similar capacitive features that overlap the second traceportion 908 and the first trace portion 906, respectively.

The mounting arm 960 is composed of a conductive material and includes afirst coupling portion 962 and a second coupling portion 964 that extendover opposite portions of the antenna 902. As shown in FIG. 12B, thefirst coupling portion 962 is in contract with the antenna trace 905and, more specifically, with a terminal plate 966 of the antenna trace905, thereby facilitating electrical conduction between the antenna 902and a feedthrough pin 968 to which the mounting arm 960 is coupled.

Disposed between the second coupling portion 964 and the antenna trace905 is a capacitive feature 920 in the form of a plate 920. The plate920 is in contact with the second coupling portion 964 and overlapping aportion of the second trace portion 908. In other implementations, theplate 920 may be shaped and positioned to overlap a different portion ofthe antenna trace 905, such as the first trace portion 906. The plate920 may be integrated into either of the second coupling portion 964 andthe antenna body 904 or may be a separate component disposed between thesecond coupling portion 964 and the antenna body 904. As more clearlyillustrated in FIG. 9C, which excludes the mounting arm 960, the plate920 is positioned to overlap a portion of the second coupling portion964, thereby forming a capacitive structure that may be used to tune theantenna 902. More specifically, the plate 920 forms a first capacitorplate, the portion of the second trace portion 908 forms a secondcapacitor plate, and the antenna body 904 acts as the dielectricmaterial between the two plates.

FIG. 13 illustrates another embodiment of an antenna assembly 1000 inaccordance with this disclosure. The antenna assembly 1000 includes anantenna 1002 coupled to a mounting arm 1060 by an antenna shroud 1066.

The antenna 1002 includes an antenna body 1004 composed of a dielectricmaterial and an antenna trace 1005 disposed within the antenna body1004. The antenna trace 1005 includes a first antenna portion 1006 and asecond trace portion 1008. The first trace portion 1006 and the secondtrace portion 1008 are disposed in offset transverse layers within theantenna body 1004 and are arranged such that the second trace portion1008 is disposed within a boundary defined by the first trace portion1006. Additional trace portions may also be included within the antennabody 1004, with each successive trace portion being disposed within aboundary defined by the previous layer. Any trace portion may includecapacitive features shaped and positioned to overlap a portion of anadjacent trace portion. For example, although not depicted in FIG. 13 ,either of the first trace portion 1006 and the second trace portion 1008may include capacitive features that extend and overlap the second traceportion 1008 and the first trace portion 1006, respectively. By varyingthe quantity, placement, and size of the capacitive features, theantenna 1002 may be tuned to improve its response to signals inparticular frequencies.

The mounting arm 1060 is conductive and is coupled to the antenna trace1005. The mounting arm 1060 is adapted to be coupled to a feedthroughpin 1068 of an IPG (not shown) and to communicate signals between theantenna trace 1005 and the feedthrough pin 1068. Coupling of themounting arm 1060 to the antenna trace 1005 is achieved through theantenna shroud 1066, which is coupled to each of the antenna 1002 andthe mounting arm 1060 such that the mounting arm 1060 is maintained incontact with the antenna trace 1005. More specifically, the antennashroud 1066 includes a surface to which the antenna 1002 is coupled.Coupling of the antenna shroud 1066 to the antenna 1002 may be achievedin various ways including, without limitation, fusing the antenna shroud1066 to the antenna 1002 using a co-firing process. The antenna shroud1066 further defines a receptacle 1070 into which the mounting arm 1060is inserted. The receptacle 1070 extends through the antenna shroud 1066such that, when inserted into the receptacle 1070, the tip of themounting arm 1060 contacts and electrically couples with the antennatrace 1005. The tip of the mounting arm 1060 (and the mounting arm 1060more generally) as well as the receptacle 1070 may have a variety ofmating shapes and are not limited to the substantially rectangularshapes shown in FIG. 13 . Moreover, in certain implementations, the tipof the mounting arm 1060 and the receptacle 1070 may be tapered orotherwise vary in shape along their lengths.

The foregoing merely illustrates the principles of the invention.Various modifications and alterations to the described embodiments willbe apparent to those skilled in the art in view of the teachings herein.It will thus be appreciated that those skilled in the art will be ableto devise numerous systems, arrangements and methods which, although notexplicitly shown or described herein, embody the principles of theinvention and are thus within the spirit and scope of the presentinvention. From the above description and drawings, it will beunderstood by those of ordinary skill in the art that the particularembodiments shown and described are for purposes of illustrations onlyand are not intended to limit the scope of the present invention.References to details of particular embodiments are not intended tolimit the scope of the invention.

What is claimed is:
 1. A method of manufacturing an implantableelectronic device, the method comprising: forming an antenna of theimplantable electronic device by delivering an antenna trace within adielectric antenna body, the antenna trace including: a first traceportion disposed in a first transverse layer and defining a first tracepath; a second trace portion disposed in a second transverse layerlongitudinally offset from the first transverse layer and defining asecond trace path, wherein, if projected to be coplanar, the first tracepath defines a trace boundary and the second trace path is within thetrace boundary; and forming a capacitive feature extending to partiallyoverlap the first or second trace portions.
 2. The method of claim 1,wherein a portion of the dielectric antenna body is disposed between thecapacitive feature and the first trace portion or the second traceportion.
 3. The method of claim 1, wherein the method further comprisescoupling the antenna to a mounting arm, wherein the capacitive featureis coupled to the mounting arm.
 4. The method of claim 1, wherein theimplantable electronic device includes a feedthrough pin, the methodfurther comprising: coupling the antenna to a mounting arm; and couplingthe mounting arm to the feedthrough pin, wherein the mounting arm isconductive and electrically couples the antenna trace to the feedthroughpin.
 5. The method of claim 1, further comprising forming a secondcapacitive feature extending from the first trace portion to at leastpartially overlap the second trace portion.
 6. The method of claim 1,wherein the antenna defines a longitudinal axis, wherein the dielectricantenna body extends along the longitudinal axis, and wherein theantenna trace further comprises a junction extending longitudinally andelectrically coupling the first trace portion to the second traceportion.
 7. The method of claim 1, wherein the implantable electronicdevice includes a hermetically sealed housing containing an electricalcircuit adapted to generate and receive radio frequency (RF) signals,the method further comprising coupling a conductive mounting arm to eachof the electrical circuit and the dielectric antenna body such that theconductive mounting arm forms a conductive path between the electricalcircuit and the antenna trace and supports the dielectric antenna bodyat an offset from the housing.
 8. The method of claim 1, the methodfurther comprising: coupling a first coupling portion of a mounting armto the antenna; and coupling a second coupling portion of the mountingarm to the antenna, wherein the first coupling portion and the secondcoupling portion are coupled over opposite portions of the dielectricantenna body.
 9. A method of manufacturing an implantable electronicdevice, the method comprising: coupling a conductive mounting arm to anelectrical circuit disposed within a hermetically sealed housing of theimplantable electronic device, the electrical circuit adapted togenerate and receive radio frequency (RF) signals; coupling theconductive mounting arm to a dielectric antenna body of an antennaassembly such that the conductive mounting arm forms a conductive pathbetween the electrical circuit and an antenna trace of the antennaassembly and supports the dielectric antenna body at an offset from thehousing, wherein the antenna assembly includes: an antenna defining alongitudinal axis, the dielectric antenna body, wherein the dielectricantenna body extends along the longitudinal axis, and the antenna trace,wherein the antenna trace forming a first trace portion and a secondtrace portion disposed in first and second transverse layers within thedielectric antenna body; and coupling a capacitive feature to theconductive mounting arm, the capacitive feature overlapping at least oneof the first and second trace portions.
 10. The method of claim 9,further comprising defining a trace boundary associated with the firsttrace portion, wherein, if projected to be coplanar, the second traceportion is within the trace boundary.
 11. The method of claim 9, whereinthe antenna assembly includes a second capacitive feature that at leastpartially overlaps at least one of the first trace portion or the secondtrace portion with a portion of the dielectric antenna body disposedbetween the second capacitive feature and the at least one of the firsttrace portion and the second trace portion.
 12. The method of claim 9,wherein the antenna assembly includes a third capacitive feature that atleast partially overlaps at least one of the first trace portion or thesecond trace portion with a portion of the dielectric antenna bodydisposed between the third capacitive feature and the at least one ofthe first trace portion or the second trace portion.
 13. The method ofclaim 9, further comprising coupling each of the dielectric antenna bodyand the conductive mounting arm to a shroud, wherein the shroud definesa receptacle to receive a terminal end of the conductive mounting armand coupling the conductive mounting arm to the shroud includesdisposing the terminal end of the conductive mounting arm into thereceptacle.
 14. A method of manufacturing an implantable electronicdevice, the method comprising: coupling a conductive mounting arm to anelectrical circuit disposed within a hermetically sealed housing of theimplantable electronic device, the electrical circuit adapted togenerate and receive radio frequency (RF) signals; coupling theconductive mounting arm to a dielectric antenna body of an antennaassembly such that the conductive mounting arm forms a conductive pathbetween the electrical circuit and an antenna trace of the antennaassembly and supports the dielectric antenna body at an offset from thehermetically sealed housing; and coupling a capacitive feature to theconductive mounting arm, wherein the capacitive feature is a plate, andcoupling the conductive mounting arm to the dielectric antenna body suchthat the plate overlaps a portion of the antenna trace and a portion ofthe dielectric antenna body is disposed between the plate and theportion of the antenna trace.
 15. The method of claim 14, wherein thedielectric antenna body defines a longitudinal axis and the antennatrace includes a first trace portion and a second trace portionlongitudinally offset from the first trace portion.
 16. The method ofclaim 14, wherein the antenna trace includes a junction extendinglongitudinally between and electrically coupling a first trace portionof the antenna trace and a second trace portion of the antenna tracelongitudinally offset from the first trace portion.
 17. The method ofclaim 14, wherein: the antenna assembly further includes a secondcapacitive feature extending from a first trace portion to at leastpartially overlap a second trace portion longitudinally offset from thefirst trace portion, and a portion of the dielectric antenna body isdisposed between the second capacitive feature and the second traceportion.
 18. The method of claim 14, wherein the implantable electronicdevice includes a feedthrough pin coupled to the electrical circuit andextending through the hermetically sealed housing, and wherein couplingthe conductive mounting arm to the electrical circuit includes couplingthe conductive mounting arm to the feedthrough pin.
 19. The method ofclaim 14, further comprising coupling each of the dielectric antennabody and the conductive mounting arm to a shroud, wherein the shrouddefines a receptacle to receive a terminal end of the conductivemounting arm and coupling the conductive mounting arm to the shroudincludes disposing the terminal end of the conductive mounting arm intothe receptacle.
 20. The method of claim 14, wherein the mounting armfurther comprising a first coupling portion and a second couplingportion, the coupling the conductive mounting arm to the dielectricantenna body further comprising coupling the first coupling portion andthe second coupling portion over opposite portions of the dielectricantenna body.